NONE
Research and development of this invention and Application have not been federally sponsored, and no rights are given under any Federal program.
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1. Field of the Invention
This invention relates to the marine inflatable device industry and, more particularly, to apparatus for inflating life preservers, vests, rafts, or similar such devices in accordance with Coast Guard and Airline rules and/or regulations.
2. Description of the Related Art
Small cartridges which hold large quantities of carbon dioxide or other gas under compression for inflating these types of devices are known. Typical are those described in the Mackal U.S. Pat. Nos. 3,809,288; 4,223,805; 4,267,944; 4,498,605; 5,058,635; and 5,333,656. As this last patent pointed out, one problem in the industry followed from the fact that a person could not quickly determine whether the cartridge attached to the inflator was spent. Since a discharged cartridge was virtually identical in outward appearance to a fully charged one, the possibility existed that the cartridge in place was empty, and not filled. As the patent noted, the only way to resolve the question was to unscrew the cartridge, and visually inspect its membrane to see whether it had been already punctured.
U.S. Pat. No. 5,333,656 addressed the problem by painting a red sign on an inflator arm, to appear in a window when the arm was in the discharge position of the inflator, to indicate that the cartridge was empty. Although the theory was that the red sign would disappear only after a full cartridge was replaced back into position, testing revealed that the red sign on the inflator arm was moved out of the viewing area no matter the condition of the replacement cartridge being reinserted. Investigation revealed that this followed from the irregular type hole the patent""s chisel-shaped pin produced when puncturing the cartridge to release its compressed gas when filling the inflatable device. The intent of the inventionxe2x80x94to show that an empty cartridge was in placexe2x80x94was thus not reliably achieved.
Further testing showed that this problem persisted even with the modified puncture pin described in Mackal""s earlier U.S. Pat. No. 5,058,635. There, it was found that its chisel-shaped head often caused the puncture hole rim to snag on the pin, and because the arrangement also included an internal spring. that was biased in a direction to exert a backward pull on the puncture pin. Such biasing was noted to sometimes snag (and lodge) on its way into the charged cartridge during its detonationxe2x80x94which interfered with the desired venting and inflation.
These puncture pin problems were overcome, however, with the safety inflator described in my own U.S. Pat. No. 5,643,030, in which the pin was provided with a cone-shaped head. With it, a perfectly round hole was created upon puncture in the cap of the gas cartridge. This puncture pin possessed a barely perceptible flat head, enabling it to bear against the cap without prematurely puncturing it, as if the head were pointed instead. With the cone-shaped configuration, the accidental insertion of a spent cartridge was automatically prevented from changing the display to improperly indicate the cartridge to be full when, in fact, it were empty.
As will become clear from the following description, the inflator of the present invention retains this cone-shaped, cross-section puncture pin, although somewhat modified, to prevent any cartridge replacement from wrongly changing a display of readiness. As will also become clear, the inflator of the invention goes one step further, in offering a construction which makes it easier to observe the cartridge condition than with my U.S. Pat. No. 5,643,030 design, and one which is more compact for use. In one version, a snap-action lever arm is employed to allow controlled detonation at even low pull tensions. In a second version, an internal signalling flag is removed to significantly reduce the size and weight of the inflator.